OP
kylebosch808
Bronze Member
So why is it that the back hoes that you buy don't have a sub frame?
Building a backhoe? Anyone ever done it?
- Thread starter kylebosch808
- Start date
- Views: 7333
Iplayfarmer
Super Member
They do. You usually have to buy the subframe separately to fit your specific tractor.
There are 3 pt. backhoes out there, but there are many backhoes that can be either 3 pt. or subframe.
jimgerken
Veteran Member
Another idea would be to make it a towable model. Typically they have their own engine and hyd pump, but you could hang the pump on your pto shaft. The towable would free the tractor of the stress even better than the subframe. Very easy to connect and use too. I have thought about a standard 3-point attach model like the low cost TaylorWay unit, converted to towable for 3-point safety.
Renze
Super Member
The italians make trailer farm backhoes:
excavator loaders
AS1070
C. Argenterio & CO. srl - Macchine Agricole - macchine agricole
a lot of them were sold here in the 80's but now you can pick them up cheap.
One of these excavators could load a muck spreader or dumptrailer as fast as a self propelled construction hoe, as long as you didnt have to relocate too often.
OP
kylebosch808
Bronze Member
ok, if im going to make a towable version i midaswell spend the money and make a excavator type that spins 360 degrese. Anyone know where to get the 360 hydraulic manifold for cheap? perferably out of a mini EX
Iplayfarmer
Super Member
Don't need it.
Mount all your hydraulics, etc. on the "turret" and mount a ring gear on the base. Then everything spins together and you don't have any hydraulic hoses needing to be rotated. Make telescoping stabilizers with pins rather than hydraulics to eliminate the need for hydraulics on the stabilizers.
My vote is still for a tractor mount backhoe. Mostly because that's what I want to make, and I expect that I'll get more inspired following your thread.
chumly2071
Bronze Member
Just be sure to watch heat build up in the hydraulic fluid restricting it this way... A better, but more expensive alternative is a flow divider. If this was in the stabilizer circuit which doesn't cycle often, it is no big deal, but for a swing cylinder that will be actuated constantly, I would be concerned with heat buildup.
chad22
Veteran Member
Dang that's a good idea. I just might implement that into my backhoe. I could have the manual stabilizers, and still just crawl it around, and when I want to turn it from one side to another. I just lift up and use the swing motor to steer it around.
Now I just need to wait until I get some more money to purchase the hydraulic motor, and extra parts. Then I can have my home made mini excavator with 360 swing.
Thanks for the idea.
Chad
Renze
Super Member
If you tow it by tractor, you could still operate the stabilisers with tractor hydraulics. But anyways, how often do you turn 360 degree when there is a tow vehicle up front ? If you put the stabiliser lines in a big loop, you could turn 360 degrees too, but just one revolution
Renze
Super Member
I try to baby that swing lever, so it lets oil escape to the return side in the valve block. but sometimes it goes a little fast. only on that occasion i need some restriction. I dont intend to yank the lever to full flow, just need a safety backup next to careful operating.
Why not regulate the fluid with are regulator to slow the swing speed down, all of the hydraulics on our Prentice Telstick33 material handling booms are regulated hydraulics. If you set the regulators correctly you can get very slow and precise movements of the main stick boom/dipper boom functions and swing even when you are running the engine at full power and still be able move the boom at a pretty good clip and not be jerky.
I have run my friends John Deere 310 backhoe and it drives me nuts because of how jerky the swing and boom functions are. I am almost positive the machine does not have regulators of they have been messed with at some point to try and improve hydraulic cylinder speed.
Last edited:
Iplayfarmer
Super Member
I screwed up they are called flow controll valves intstead of regulators. Here is a picture of what they look like.
That valve does the same thing that Renze does with his laser cut washer. It just restricts the flow. The one advantage of the flow control valve is that it can be adjusted in situ.
Renze said:
The stabilizer operation is a major drawback to the "no-manifold" solution, but at $1450 for a rotary manifold it's easy to justify some compromises. I understand that manual stabilizers are actually fairly convenient on a towable unit. The boom will easily lift the rig enough to drop the stabilizers.
Iplayfarmer
Super Member
You can probably get what you need for the ring gear and pinion by scrapping out a rear axle of some defunct vehicle.
Another thought regarding the swing speed... In my design, I purposely included a larger diameter swing cylinder anticipating that I'd want to slow it down a bit.
Renze
Super Member
At work, the Parker M200 loader valve can set flow and pressure per section... But at home i must keep cost in mind, because i cant make those 15 to 25.000 hours to amortise the expenses...
Any flow controlling device in a system with fixed displacement pumps, will generate heat and waste fuel revving the engine down is the cheapest way to speed down movements...
At work, the Parker M200 loader valve can set flow and pressure per section... But at home i must keep cost in mind, because i cant make those 15 to 25.000 hours to amortise the expenses...
Any flow controlling device in a system with fixed displacement pumps, will generate heat and waste fuel revving the engine down is the cheapest way to speed down movements...
This is true they are on the pricey side and I completely understand not wanting the added expense to the project. The only thing that concerns me is when you reduce the engine RPM is you loose pressure and put more strain on the pump and engine because it's not running in it's power band trying to do the same work. I have had to use our boom when the high idle switch quit working on me and both the engine and hydraulics worked really hard to move what I was unloading that normally would not even phase the engine or hydraulic pump at 1500 RPM instead of idleing at 600-750 RPM. You could always use the laser cut washers that were mentioned as an less expensive way to regulate the pressure and speed of the swing cylinder.
Listen to the load that get's put on the engine in this video until he up's the idle. There is a reason why excavators and backhoes run at the RPM's they do.
Cub Cadet 149 - YouTube
Renze
Super Member
This guy doesnt have his ratios right: The engine too small, the pump too big or the pulley ratio too tall. When i use it on my 3011 i put the gear range lever in neutral, switch the combined PTO/pump drive to ground driven, and put the transmission in 4th gear. That way i get full flow at only 1400 engine rpm. It doesnt even lug the 40hp engine down one bit. Most mini excavators (1 to 1.5 ton) comparable to my Bobcat backhoe have about 18hp.
With the 20 liter of oil in a 1000kg cast rear end, i'm not too worried about heat buildup.
Sounds like you have a very nice set up, I learned something new today thank's. I am going to get my John Deere 317 project tractor tomorrow and I will be tearing in down in a couple weeks to start a loader/backhoe build of my own over the winter. If you don't mind I may need to pick your brain from time to time.
Dave
Here are some similar links:
